Car exhausts have got increasingly complicated over the years, but at heart they are still just long pipes that take waste gases from the engine and allows them to exit at the rear of the vehicle.
Along the length of your exhaust, you will probably find a couple of extra bits:
- One or more silencers – these are metal cylinders that help reduce exhaust noise
- A catalytic converter – catalysers or cats, as they are sometimes known, help reduce some of your car’s more harmful emissions. They usually look like a large bulge in the exhaust pipe.
Most exhausts come in three sections:
- The downpipes from your engine – there will probably be four of these, one from each cylinder.
- The mid-section – this will be a single pipe and will probably include a silencer and perhaps the catalytic converter
- The rear section, often known as the back box. This will include another silencer and some pipe to join it to the midsection and/or catalytic converter.
The most common problem with exhausts is corrosion. This leads to holes in your exhaust which make it sound louder and more flatulent and which will result in it failing its next MOT.
If it gets too rusty, it may fall off. If it’s the back section that has fallen off, your car will probably still work without it, but everyone will hear you coming and you will need to get it fixed fairly quickly.
Cars used for short journeys or not much at all are particularly prone to rusting exhausts because one of the waste products of engines is water. If your car’s exhaust never gets properly hot, water will sit inside the pipes and gradually rust them.
The other possible problem with exhausts is a failed catalytic converter. This is quite bad news as they are expensive and your car probably won’t pass its MOT without one. Fortunately, most catalytic converters last for the life of a typical car.